Well, I got the lens, complete with the obligatory UPS trashing of the box, but the lens seems OK. On flat targets it focuses sharply, but leaning in causes blurring, shile stepping back does not, so I expected to have to adjust for backfocus. I set up Yvon Bourque's telephoto lens chart, and surprisingly it was right on the money or nearly so at several focal lengths - can't quite explain it, but I set it up on a tripod (very heavy combo with the K20 and BG-2 grip) in my dining room with the door open and waited for the butterflies to alight. I used the widest aperture for the shallowest DOF at longest focal length and here is a sample of what I got. Focus is right on. I will post more later.